The sight of a Slow Loris (Nycticebus menagensis) staring down at you from the rainforest canopy, its eyes brightly illuminated by your headlamp, is always an exciting find. It was only three weeks ago, whilst I was on a nocturnal foray with a group of photographers in the jungles bordering Sarawak and Kalimantan, that I had my most recent encounter with a loris. Unfortunately, these nocturnal primates are nowhere abundant and sightings of them uncommon at best, due in part to patchy distributions and also sadly, capture for the pet trade.

A new paper in American Journal of Primatology presents a dramatic new view of the loris diversity in Borneo. Previously, three subspecies of loris were known from the island: N. m. bancanus, N. m. borneanus, and N. m. menagensis, which differed from each other in fur coloration and body size. However, taking into account other recent findings in loris diversity, the reseachers of the present paper undertook a thorough investigation on the variation of Bornean lorises, which had never been studied in great detail.

After critically examining a number of museum specimens and carefuly comparing their morphology and corresponding geographic locations, they concluded that there were not three, but four distinct loris types on Borneo, and went further to elevate each of these to its own species status. Thus the presently recognized species now include: N. bancanus, N. borneanus, N. menagensis, and the new N. kayan.

Several months ago I received an email from Dr. Anna Nekaris, who heads The Little Fireface Project, a non-profit organization dedicated to loris research and conservation. She pointed out that one of the animals which I had photographed in Sarawak several years ago represented the newly described Nycticebus kayan (pictured below). Specifically, the Kayan Loris can be distinguished from other Bornean lorises by a combination of features including its highly contrasting and distinctive face mask.

Like all lorises, the Kayan Loris is primarily nocturnal and feeds on a variety of insects and soft fruits. Lorises are also unique among primates in that they possess a venomous bite which is used in self-defense. The bite can cause fever, pain, and swelling, and in people who happen to be allergic the results may even be fatal. One Sarawakian who I met in Mulu National Park, had to be hospitalized for several days after being bitten when handling a wild loris.

Although more research, including genetic studies, remains to be done on Bornean lorises, the new discovery helps not only to shed light on the variations of these nocturnal primates, but also is a testament to the amazing diversity which is continuing to be revealed within Southeast Asian rainforests.

References:

R. Munds, S. Ford, K.A.I. Nekaris. Taxonomy of the Bornean Slow Loris, with New Species Nycticbus kayan (Priamtes Lorisdae). American Journal of Primatology, December 2012; DOI: 10.

In late 2010 I was fortunate to be able to join a team of researchers investigating animal interactions with the giant pitcher plant Nepenthes rajah. Endemic to the cool and mist-shrouded slopes of Mount Kinabalu and Mount Tambuyuon in northern Borneo, this is not only one of the world’s largest Nepenthes but also the source of the original stories of “rat-eating” carnivorous plants. There exist a number of confirmed incidents of this plant consuming small mammals which are unfortunate enough to fall within the voluminous pitchers. Recent research however, has shed light on a far more interesting and complex animal/plant relationship, and prior to our 2010 work it had been already shown that the Mountain Treeshrew (Tupaia montana) visits the pitchers of N. rajah (as well as several other Bornean Nepenthes) to feed on the sweet nectar exuding from beneath the pitcher lid. The plant benefits from these visits by frequently collecting the treeshrew’s scat which fall inside the pitcher and are a valuable source of nutrients.

During the field work it was observed that some of the animal droppings found on and in the pitchers appeared different than those left behind by the Mountain Treeshrew. However, despite many days of watching the plants during daylight hours, treeshrews were the only mammals seen to visit the plants. It wasn’t until camera equipment was left in place to monitor the plants during the night that we ascertained the presence of another animal, the Summit Rat (Rattus baluensis) at the pitchers. This is the first instance confirming a rodent/Nepenthes relationship, and it is presumed that it matches the treeshrew/Nepenthes mutualism albeit nocturnally. The photo here, the first ever to illustrate this interaction, shows an image I obtained at night by use of an infrared camera trap positioned adjacent to the pitcher and illuminated by multiple strobes.

Unlike the related Nepenthes lowii, another Bornean pitcher plant which has lost its means to trap insects and depends entirely on the treeshrew droppings for its nutrients, N. rajah retains its carnivorous apparati, a slippery peristome and smooth pitcher walls, and still consumes prey. It is quite likely that the records of rats and treeshrews having drowned in N. rajah pitchers were not instances of these mammals seeking out a source of water (as has been assumed in the past), but rather the result of unfortunate animals falling into their “toilet”.

References:

Chin, L.J., J.A. Moran, C. Clarke (2010) Trap geometry in three giant montane pitcher plant species from Borneo is a function of tree shrew body size. New Phytologist 186: 461–470.

Clarke, C.M., U. Bauer, C.C. Lee, A.A. Tuen, K. Rembold (2009) Tree shrew lavatories: a novel nitrogen sequestration strategy in a tropical pitcher plant. Biology Letters 5: 632–635.

Greenwood, M., C. Clarke, C.C. Lee, A. Gunsalam & R.H. Clarke (2011) A Unique Resource Mutualism between the Giant Bornean Pitcher Plant, Nepenthes rajah, and Members of a Small Mammal Community. PLoS ONE 6:6.